Switching to VoIP

This is the Title of the Book, eMatter Edition

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Chapter 17

CHAPTER 17

Asterisk Reference

Earlier in the book, we covered compiling and installing Asterisk, installing a legacy

interface card and drivers, and setting up some simple PBX applications. Later on,

we used Asterisk configurations to illustrate some common enterprise telephony

concepts. This chapter is geared toward the person who’s comfortable with the ear-

lier material in the book and wants a deeper understanding of Asterisk.

Asterisk is a deep subject that touches disciplines of networking, code-writing, proto-

cols, and standards. This chapter won’t make you an Asterisk expert, but it should

help you go a step or two beyond the essentials we’ve already covered. We’ll cover

channel configuration—with an emphasis on Zaptel and SIP channels, dial-plan syn-

tax elements like variables and string processing, and the commands you can use in

building an Asterisk dial-plan.

How Asterisk Is Supported

Asterisk’s principal sponsor is a firm called Digium, based in the United States. The

company provides development leadership and commercial support for the open

source system. It also manufactures and distributes the Wildcard interface devices

and iAXY ATA used in some of the projects in this book. A number of independent

consultants provide commercial support for Asterisk. Subscribing ...